Nearly 6,000 instances of sexual assault, including more than 450 cases of rape, were reported to Uber in the United States in 2017 and 2018, the ride-sharing company said in a report on safety released Thursday.

It is the first time that Uber has released the figures -- which also revealed 19 fatal assaults related to the company over the two-year period -- as it and rival Lyft face increasing pressure to cope with the growing number of complaints of abuse.

The company received 464 reports of non-consensual sexual penetration and 587 of attempted non-consensual sexual penetration in 2017 and 2018.

The other assaults fell into categories such as non-consensual kissing or touching.

While the number of reports went up from 2017 to 2018 in three of the five categories, including non-consensual sexual penetration and non-consensual touching of a sexual body part, the ride-sharing service hailed across-the-board declines in the "incident rate" based on a larger number of overall trips occurring in the latter year.

"From 2017 to 2018, Uber saw approximately a 16 percent decrease in the average incident rate across the five most serious sexual assault categories reported. Additionally, there were rate decreases across each of the five individual categories," the report said.

Uber also reported 10 "fatal physical assaults" related to its service in 2017 and nine in 2018.

"During 2017 and 2018, there were 19 fatal physical assaults occurring in a total of 18 incidents in relation to Uber," the company said.

Of the dead, eight were riders, seven were drivers and four were third parties including bystanders, Uber said.